A British exit from the European Union is the greatest threat facing the country's economy in the next decade, Ed Balls will say as he attacks Conservative ministers for creating uncertainty for the country's businesses.

The shadow chancellor will acknowledge the need for reform of the EU but will hit out at David Cameron's policy of offering an in/out referendum, warning the Tories are "flirting with exit" for narrow political party interests.

Labour frontbenchers Mr Balls and Chuka Umunna will address the British Chambers of Commerce annual conference and stress the party's pro-business agenda following a string of attacks from senior corporate figures in recent days.

Mr Balls is expected to say:

Because Britain walking out of the EU is the biggest risk to our economy in the next decade. EU exit risks British jobs, trade and investment and the future prosperity of the UK.
And every comment by senior Cabinet ministers saying they would be happy or relaxed to see us walk out, and every hint that a referendum could happen as early as next year - before any meaningful reform agenda could be achieved - only adds to the uncertainty and risk for British businesses.

"He’s not into the whole PR thing and if we’re honest about it I don’t think there are that many politicians that people attribute those qualities to

"And by the time we get to the next general election hopefully we’ll have the debates and the Prime Minister will stop playing chicken on that, and we’ll have the debates and people will be able to see even more of Ed than they have already."

Also on the panel will be the Editor-In-Chief of ELLE UK, Lorraine Candy, the Chair of the Arts Council England, Sir Peter Bazalgette and the author and Fleet Street Fox blogger, Susie Boniface.

The panel will be discussing campaigns, including ELLE's "This is what a feminist looks like" campaign, Labour's fortunes and power dressing.

Today's appearance from Pfizer bosses before MPs "confirms many of the worst fears" about the proposed takeover of AstraZeneca, Labour have said.

Shadow Business Secretary Chuka Umunna told the BBC: "What we heard at the hearing today reinforces the grave concerns we have about this deal and confirms many of the worst fears of people in the business and science community in the UK.

Ian Read appearing before MPs earlier. Credit: PA Wire

"What do we know? They confirm that they will be cutting jobs. They confirm that there will be a cut in the spending of the combined merged entity. They've confirmed that the business, AstraZeneca will be split up, and they haven't ruled out selling off parts of it in the future.

"The assurances Pfizer has given Ministers are not worth the paper they are written on, given that Pfizer has since refused to rule out breaking up the AstraZeneca business and selling off parts of it in the future if this takeover proceeds."

Mr Umunna called on ministers to order a "proper, independent assessment of the takeover" to determine whether it is in the public interest.